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Microfilmed copies of the Census schedules from 1790 to 1920 (1930 after April 1, 2002) are available at the National Archives Building, 700 Pennsylvania Avenue, NW, Washington, DC; at the National Archives Regional Offices (see Appendix A); and through the National Archives Microfilm Rental Program. Title 44, U.S. Code, allows the public to use the National Archives' census record holdings after 72 years, thus the 1790 to 1920 records are available to the public on microfilm from the National Archives. After April 1, 2002, individual records from the 1930 census will be made available. The U.S. Census Bureau holds only the records for 1930 through 2000 (after April 1, 2000, the Census Bureau will hold census records from 1940 to 2000). The agency's Personal Census Search Unit, in Jeffersonville, IN, maintains and searches these records, which are confidential by law (Title 13, U.S. Code). As a result of fire, damage, or other loss, census records on microfilm are not entirely complete. The most notable gap in coverage is for 1890. As a result of a 1921 fire at the Department of Commerce, surviving records are limited to portions of Alabama, the District of Columbia,
Carolina, Ohio, South Dakota, and Texas plus the special 1890 schedules enumerating Union veterans of the Civil War and their widows for Kentucky and Wyoming (See Appendix C). Figure 1 shows the decennial population schedules from 1790 through 1920, together with SOUNDEX indexes for 1880, 1900, 1910, and 1920, for which microfilmed copies are available for public use through the National Archives, its regional branches, and at libraries in various parts of the country. (Pursuant to Title 44, U.S. Code, the National Archives will open the 1930 records to the public after April 1, 2002). The National Archives sells or rents the microfilm publications listed on the chart to individuals and institutions, and some libraries are willing to release copies through interlibrary loan. The National Archives periodically issues catalogs for use in ordering the microfilm and publishes checklists of institutional holdings. See the bibliography Electronic data processing. In the mid-1940s, the Census Bureau and scientists from the National Bureau of Standards began studying the use of electronic computers for large-scale data processing. In 1951, the Census Bureau acquired the UNIVAC I built according to the Census Bureau's requirements and experimental processing began following the 1950 census. Together with a second UNIVAC, tabulations were successfully completed for a number of programs, including the majority of the 1954 Economic Census.
'A form BC-600, “Application for Search of Census Records," is required to obtain census records still held by the Census Bureau. This application can be downloaded, using Adobe Acrobat from the following address: www.census.gov/genealogy/www/bc600.pdf.
Measuring America To meet the needs of the 1960 Census, the Census Bureau obtained two new 1105 computers in October and December, 1959. As a result of a cooperative agreement between the Census Bureau and the University of North Carolina and the Armour Research Foundation of the Illinois Institute of Technology, a UNIVAC 1105 was installed at each university that was compatible with those housed at the Census Bureau. Each university allocated two-thirds of the "productive" time on its computers to the census, with additional time (in lesser amount) being afforded the Census Bureau upon completion of the 1960 Census process. ing. The Census Bureau also employed the film optical sensing device for input to computers (FOSDIC). The FOSDIC scanned microfilm copies of appropriately designed questionnaires, read the marks entered by enumerators, and transcribed the information to reels of magnetic tape readable by computer. When installed on the computers, the data on these tapes were reviewed, tabulated, and finally transferred to other tapes used by high speed printers2-speeding the compilation of census data and making the hiring and training of 2,000 people dedicated to the manual preparation of punch cards obsolete.
Microfilm. In most cases, census schedules and questionnaires were microfilmed many years after they originated, by which time the ink often had faded and the pages were brittle. To save valuable storage space after filming, the paper copies were destroyed or (as was the case with the 1880 census) offered to state archives. While schedules from the period from 1790 to 1880 usually were stored flat in binders secured by cloth tape, later ones, such as the 1890 through 1920, were bound for safekeeping and ready use (for age search, etc.) in large volumes. When microfilming began around 1940, it was impractical to remove and rebind the pages in those volumes, so they were photographed in place. The pages were turned for filming, and their legibility, poor at best, sometimes was reduced even further by the camera's inability to focus on the curved surfaces of some pages. For the years beginning in 1890, when punch card tabulation came into use, clerks used red ink to add alphabetical or numerical codes in certain schedule columns (such as the one for veteran status) for the keypunch operators' guidance. These codes represent occupation, number of persons in the household, and the like information already appearing on the schedule. As the microfilm is only in black and white, this color cannot be distinguished. The reader should recognize and ignore these codes as extraneous when transcribing or interpreting what appears on the film.
2 High-speed printers received data for printing from the mag. netic tape reels created by the electronic computers. Data represented by the magnetized “spots" on the tape were printed as tabulations (600 lines per minute) which could be photographed and reproduced by the offset printing process.